Telephone system



Sept. 3, 1929. H. M. FRIENDLY 1,725,932

TELEPHONE SYSTEM Filed may 16, 1927 3 Sheets$heet 1 .5 I Q Q E 4 k E k, I: n

r -Ira/12111131"- I Herberi-P'I-Friendly 5 V I A Sept. 3, 192 H. M. FRIENDLY TELEPHONE SYSTEM Filed May 16, 1927 v 5 Sheets-Sheet 2 Invanmr Herb srHT-Friendl I Aflg- Sept. 3, 1929- H. M. FRIENDLY TELEPHONE SYSTEM 3 Sheets-Sheet 5 Filed May 16, 1927 T ELDQ mm Patented Sept. 3, 192 9. I v

- maesz UNETED STATES HERBERT M. FRIENDLY,

smear orsica.

OF CHICAGO, ILLINCIS.

TELEPHONE SYSTEM.

Application filed May 16,

The present invention relates to telephone systems; more particularly such systems as employ manual switching apparatus at the central ofiice wherein an operator wholly or b partly manually extends desired connections.

However, features of the present invention have adaptations to so-called automatic or machine switching systems, and other uses. General objects.

i The general object of the present invention is to enable the operator to respond to calls,

complete the desired connections and time the 26 pleted connection is effected.

' It is well known to have so-calledpre-payment telephone 5 'bscriber stations provide with mechanism for receiving a vfive-cent or other coin (or token) before or after an operator responds to the subscribers call for servvice. This coin or token may-be deposited in the company till of the mechanism, or it may be refunded to the subscriber any time after it is deposited for service at the will of the operator. If the connection cannot be completed it is refunded; If the connection is-completed the specific coin (or token) entitles the subscriber to apredetermined length or duration of conversation or service con-- nection. The operator is therefore charged with watching each connection made so that she may intrude on'the connection when the said predetermined time has elapsed to inform the calling subscriber that his time paid for has expired and thereupon cause the coin to be deposited in the company till. The said subscriber can then hang up hisreceiver to terminate the service and cost to him, can elect to continue it by depositinganother coin covering the duration of another period.

It is also well known to have a so-called meter register companion to and specific to' each subscribers line; the operator depressmg a key at Wlll to register a charge for a connection on the meter register 'for a service of the calling subscriber or 'he 1927. .Serial No. 191,578,

predetermined duration. However, these meter registers are usually arranged so that but a single registration can be made for a call without first withdrawing the operators answering plug of the cord pair used, though the latter is not essential and may be done away with by omitting a specific locking windingprovided on theregister magnet of the meter.

An embodiment of the present invention contemplates that the subscribers stations having a pre-payment coin mechanism referred'to as well as the stations havingthe meter registers, out change so far as the respective subscribers stations are concerned. However, a salient object of the present invention is the provi- -sion for automatically'varying through the agency of clock or time unit controlled apparatus and signals the time a connection may endure for .a specific charge, subject to the operator, depending vupon the time of day the service is rendered.

It is also well known that the cost of manually establishing a connection between a callor both, be employed withi ing and a called subscriber by an operator or operatorsgis a total costs tov the operating concern for rendering the service. That is to say, the carrymg charges on the investment converted by may, depending upon the size of the exchange and the route of the call, amount to several timesthe mere manual efiort costs entailed inefi'ecti ng the specific connection. The said carrylng charges may include interest, deprerelatively small portion of the 1 because of the service ciation, plant operating, maintenance and 7 other fixed and variable charges attaching .to

the portion of the plant exclusive of the part for providing service connections to-subscribers and not service itself. l

Where a subscriber does not call for service the portion of the plantprovided for common use in inter-switching is not called for by him,

and therefore should not be charged against the subscriber. Of course, subscribers do call for service at one time or another, but the divergency of trafiic factor has been found tocon'form to averages which permit of the operating company anticipating the demand for switching service and providing forthe necessary amount within reasonably close limits, so that the fact that a subscriber does not call for service at all practically all does not follow that any-plant used in interswitching is held in idleness or readiness to serve awaiting his call for switching service.

It is found that during certain hours of the day calls will be made in greater numbers than at others, and this call characteristic will vary with the class of subscriber. Obviously, business subscribers will, in general, call exclusively during the few intense business hours of the day. Other subscribers not governed by the characteristics of business will alsoeall during these hours in place of anticipating or deferring such calls to nonbusiness hours.

However, it is found in the larger exchanges, that a pronounced peak in traffic occurs during relatively short periods during the mid-morning and mid-afternoon, and the operating company must provide interswitching plantto meet these relatively short periods of large service demand, while much of this plant remains in idleness the rest of the time as non-productive investment.

Of course, rates, in general, must be made which will support the investment through its non-productive hours, regardless of how brief the period of its actual employment, because plant must be provided to take care of the peak demand.

Heretot'ore, so far as I am aware, no inducement has been made to subscribers charged a specific minimum toll for a call to make their calls at o fl peak times or to limit the holding of inter-switching plant involved in the call to the minimum during the hours of peak traffic density so that a given capacity of switching plant will handle more calls intotal and also during the peakhours or periods.

It will take practically the same amount of inter-switchin equipment to handle a predetermined nuniber of individual calls during 1 the peak trafiic hour or busy hour wherein the average holding time of the equipment is five minutes as twice this number of calls held durlng the same time wherein the average holding time of the equipment for each call is two and one-half minutes, because in a stated time wherein the calls endure only two and one-half minutes twice as many subscribers are enabled to use the total installed inter-switching equipment, or twice as many calls may be made by the subscribers at large.

It is thus clear that it subscribers will reduce the average holding time of'calls over the busy-hour or peak periods, a lowertotal plant investmentfor handling the peak traffic will result which will be reflected in lower costs or rates to subscribers without prejudice .to the operating concern. The investment in trafiic handling plant is more than twice that of the subscriber plant in large exchanges.

By making the time a connection may be held for a specific charge vary inversely with respect to the busy hour will discourage long conversations being made during times of the day when there is large demand for service and wherein equipment must be installed expressly in contemplation of this demand and which in large part remains in idleness at other times.

Again, long conversations, perhaps includingn'1any-ot a social nature. will be anticipated to or deferred to off-peak times where a longer conversation may be held for the specific charge for a conversation. out of purely pecuniary considerations. This will re duce he amount of traffic handling equipment necessary to handle the peak trafiic since it shifts the demand'trom' logical peak time and therefore reducesthe plant investment and attendant costs of furnishing solely switching serviceto subscribers at large. In other words, the present invention looks to raising the load or tratlic density factor of the trallic handling portion of the system whereby a lower investment will sutlice to handle a given total traflic in number of calls and aggregate duration of calls throughout a twenty-tour hour period.- It encourages profitable elf-peak trafl ic handled by available equipnwntand it discourages on-peak traflic which must be handled by equipment that has to be installed expressly for such trallic,inl.arge part. i

In order for theoperating concern to receive pay for the plant investment not used solely in handling trailic, a flat rental charge would be made all sul'iscribers covering plant investment specifically entailed in their in-- struments or equipn'ientsand linesterminating in the central office in' subscribers equipment. This rental will then cover the sub scriber plant costs as distinct from trafiic handling plant costs. Thusfone portion of the plant investment and carrying charges attendant upon same is supported by a fiat rental charge apportioned among the subscribers. at large, and which charge may be governed by distance and special. equipment peculiar to each subscriber within certain limits of classification. The subscriber not calling torsorvice thus pays hisequitable share towards the investment occasioned by him as nearly as can. be practicably ascertained. A subscriber, though he may not be a user of the service in making outgoing calls (his incoming calls being paid .for by the calling partywho maybe assumed to the one benefited) will still be a profitable subscriber to the operating concern. V

The trafiic handling portion of the plant and attendant operating and carryingcharges is apportioned to the subscribersas and when they call, having in mind that oft-peak tratfie uses switching equipment which was primarily installed for peak traflie, regardless of off-peak traffic. I

The present invention thus provides "for apportioning costs to subscribers in the relatioiiship of the in\-' estn1cnt,o pera ting and eartherewith.

rying costs occasioned by them individually, because of the peculiar requirements and traffic demands made by each.

charges to them are an actual index of their demands upon the operating concern, taking each call into consideration, as distinct from charges or rates based upon general averages of total exchange costs and which operate in favor of .the user of on-peak udices the user of off-peak trafiic.

The methodand means contemplatedby the present invention thus enables each call to'be classified by-the time of calling as distinct from methods and means employed heretofore which seek to classify in advance by. the nature of the subscribers endeavors without considerations of personal inclinations in demanding service by the subscribers individually. The present invention thus looks to making costs to subscribers based upon the circumstances of every call made and the specific facilities provided the individual subscribers in the way of equipment individual to them.

Another feature of the present invention is the provision for the operator to variably set for different zones so that specific rates may be made for various distances within the exchange area and to suburban or long distance points. This is done by means of zone keys for the respective cord-pairs so that by setting'the proper'key will cause the call to be specifically timed and rated in accordance There are a number of additional operafive features of the present invention which will be described in part in descriptions to follow relating to the exemplary emb0diment of the present invention chosen toexlain it, having in mind that other features not specifically mentioned will be apparent from the descriptions, the invention being capable of varied modification without departing from its scope as defined by the claims.

F Drawings.

With reference to the accompanying draw- Fi g. 1 shows an A operators cord circuit and accessible lines, andoperators telephone and other equipment common to a plurality of similar cord-pairs not shown.

Fig; 2 shows a timing switch Band devices companion to the cord-pair shown in Fig. 1

Fig. 3 shows meter mechanism and shiftplate restoring mechanism for the zone keys shown in Fig. 2.

Fig. 4} shows a pr ferred modification of the circuits for use in certain classes of calls so that the second period will be the same length as the first period, and moreover, conform-to absolute clock time, the timing apparatus.

It thus equitably classifies the various subscribers, so that within the accuracy, of.

' Fig. 5 shows a detail circuit scheme for varying the speed by clock or timing unit control of one of the ground interrupters (16) for operating the timing switch (B) in Fig. 2. Fig. 5A shows a plan view of two indicated hour segments, alsoshown in Fig. 5, some what enlarged.

Fig. 5B shows an edge View of the segments shown in Fig. 5A.

Fig. 6 shows a preferred modification of the circuits to flash the regular answering cord supervisory lamp (145) in place of glowing a specific lamp to attract the operator when the period pro-paid for has expired, or the unit subject to being registered on the meter has expired.

Fig- 7 shows a preferred. 'modification wherein the stepping of the timing switch B is dependent upon .the calling subscriber holding the receiver off the switchhook.

I E quip meat.

Bell telephone system, such cordance with the present invention. It will 2 be noted that the motor magnet (65) causes,

the set of wipers on the shaft to advance only the upon the retraction of the armature of motor magnet, and also that the said set. of wipers have only an advance However, in accordance with the present inmovement.

venti'on, the wipers have a normal or idle home position, as shown'inthe drawing to which the wipers return whenthe cord-pair companion to the switch becomes out of service, as by removing the completing plug (as 48) of the cord-pair from a jack. I

, The ground interrupters-lfa to16 are each driven by an electric motor (as C) or other suitable driver, controlledv by a clock or manually so that the speeds of the said interrupters 13 to 16 will each independently vary in accordance with the time of'clay in correspondence with a schedule prepared by the operating concern. The .latter'isso thatthe timing operations controlled by the various ground interru V ters' will provide for a charge based upon a determination thereof in view of costs andother factors of rendering serv,. ice, looking toward rendering service that will equitably proportion the total costs therefor to the subscribers calling for the investments involved, having in mind that the subscriber does not expressly occasion investment in switching or trafiic handling equipment unless he actually calls for service. The investment covering this trafiic handling equipment, and therefore the cost of rendermg any service actually called for will be deconsistent with their subordinated demands upon the investments and costs of tlie'operating concern as determined by rate-making bodies as equitable.

The extra charge made for preferential time of service involved in the restricting of line holding time by .the influence of rates during logical peak periods will conduce towards fewer lines being encountered asbusy at the peak periods whereby many calls are futile notwithstanding the usual effort applied in successful call connections has been expended in an efi'ort to complete them without specific compensation to the operating concern. w

Operation;

Upon the subscriber at telephone A removing his receiver to initiate a call the well known line relay (not shown) associated with the line-cut-ofi' relay 8 will operate and thereby cause the-Well known calling lamp (not shown) to glow as a calling signal. The

operator upon noting the glowing lamp Will insert the plug 12' into the jack 24-, operating the line-cut-ofi' relay 8 to extinguish the calling lamp.' The operator then manipulates her listening key 26 in order to connect .her

telephone circuit (not completely shown,.

but indicated) in talking relation with the calling line. The apparatus thus far brought into service is well known, by 5A? operators in common-battery manual operation in the Bell system.

' The'operator will now use the completing plug 48.to extend the connection to the jack 49 of the desired line leading to telephone A within her reach or through a jack 50 or'51 and'over a respective B operators trunk in the direction of the called line in the well known manner.- The operator may now restore the listening key 26.

Response 0 fcalled subscriber.

-Upon response of the called subscriber at telephone 'An -(or other called subscriber), the supervisory relay willenergize to extinguish lamp 56 in the well known manner, and further, apply ground from armature 58, make-before-break spring 60 to the winding used extensively of relay 61, the latter relayactuating and locking to the winding of line-cut-ofl relay 52. The ground from armature 58 is also applied through bank contact 62 of switclrB, wiper 63,- interrupter armature 64; of the motor magnet 65 to the win ding thereof, causing the six wipers rigid on shaft (36 to advance off the resting position'as shown in the drawing,

to the next position whereat wiper 63 rests on the left-hand end of bar 68 and wherein due .to the latter bar being grounded through armature 69 the motor magnet will rapidly .operate' by interrupting its winding to step the wiper 63 to bank contact 70, the other wipers on the shaft 66 occupying corresponding aligned bank positions. v

At this time w1per72 is resting upon the left-hand end of bar 73. A circuit can now be traced from motor magnet 65, wiper 72, bar 73,'spr ings T4 and to ground interrupter 15. The motor magnet 65 is thus now under the control of the ground interrupter 15, which causes the wipers on'the shaft to step advance consisteiit'with the speed of rotation and number of live segments of the .90 interrupter 15, remembering that this speed will vary in a predetermined way in accord-' ance with the time of day, as will appear presently. -v

Advance tone to apprise con versers that end 0/ period 28 near.

)Vhcn the wiper 72 reaches bZlHlLCOHtZlChT'? it becomes under the influence of the ground interrupter 78 and the latter interrupter pre erably, though obviously not necessarily, revolves at a uniform rate irrespective of the time of day for a definite object, as will appear presently. At this time'the wiper 80 is resting on bank contact 81, so that tone from source T is being applied through listening key spring 36, audible to the parties talking through the cord-pair.

Advance and initial period terminating tone timed for brief application.

I In this connection, it is to be particularly noted that the interrupter eoinmutators '78,

82 and 83 are linked together by the same revolving shaft or' through any, kind of gear ing and timed so that the tone from the source T or T will only be applied from the bank contacts 81 and 101, respectively, through wiper 80 one time for a relatively brief period while wiper 80 is resting longer on bank contact 81 and 101 at about the time the wiper 80 is set upon the concerned contact, so as to not unduly annoy the conversers connected through the cord-pair.

second intervals so wiper 80 will rest for this time on each of contacts 81 and 101. The tone applied from source T indicates to the connected subscribers that a predetermined time, fifteen seconds in the present assumed in- The said interrupter 7 8 may apply ground impulses at say fifteen latter may constitute a single'registration on the call meter 90" or be the collection of a coin of minus polarity through keys 87 and 88, respectively,'will answer theinserted before the conversation started; If the latter,

' The well known 7 used extensively forfive-cent'prepayment subscribers in the Bell system wherein' the coin 'is collected by "thebperator at will by applying '110'volts ofplus polarity or refunded by the apperator applying 110 volts the agency of stated requirement p Tone is applied ,when, initial period has terminated y L fWhe n the wiper 91;reaches' bank contact 92 ground is thereby applied through makebe'fore-break spring 93 to the winding of slowreleasing 'relay94, the latter relay actuating and locking to the'winding of the line-cuto'lf relay '52. The ground'japplied by Wiper 91 to bank contact 92 gizes relay f95', locking it through the springs .96, 97, 98 "to groiuided spring 99, the cordpairtime -lamp'100 glowing 'toindicate' to the operator that the initial period has'e'xpired, w l'ile th'e distinctive tone applied from tone source T through-bank contact 101, Wiper 80, listening key spriiig'36 to the tip conductor of the eord pair notifies the subscribers of the connection that theinitialperiodhas expired.

Timing of tone; applications. The; interrupter 83, timed with reference to the interrupter 82, has itslive segment somewhatlonge'r that the l'ivef'segment on'the interrupter 82 so thatthe tone from source T will not'only be distinctive in character, but will be applied so'lnewhat long'er than the tone from source T The tones while disceinable to tlie users' are preferably as unintrusive asisc onsistent with semi p rp se. Depositof coinl-for succeed'ing period.

The calling subscriber now beingin readincssto make deposit of, an additional coin, or understands that the operator will register an additional calli charge 'on the meter'ifhe desires Q to continlie "the connection, having in mind that if the inetermagne't-90 has a locking circuit as shownin the drawings it wil be necessary to, momentarily Withdraw the plug '12 to unlock the meter: magnet before a second registration can be effect d, The

locking winding oflthemeter magnet 90 (on "left-hand end'of core) will therefore be preferably omitted};iii order to obviate withd'rawingthe'plu When 'the wiperleav'es bank contact 101 it next engages bank contact 102, upon which the coin mechanism at the sub scribers station A may be any well known] coin-collecting mechanism.-

' mecl'ianism the glowing "of the time also operatively ener;

' allowing specific charge ng the stated; Adeanoe notice always have the same,

it normally rests; However, since bank con-- tact-62 is. grounded by armature 58 :the shaft 66 will forthwith advance its wipers onestep oibar10 3f Successive period longer than initial period.

"If it is assumed'thatthe subscribers elect to continue the conversation into the second period, the operator havingthereafter collected the-second toll, orwill as soon as she notices lamp 1 100, which reoneof springs 97, 98 or so that Wiper 7 2 rests upon the left-hand end mains glowing until 99 is operated incidental to eifecting a collection of the coin or the callmeter charge, or a specific key having spring 96 is operated. The motor magnet 65'will now be under the con- .trol of ground interrupter device 16 and'bar 103'in'lieu of ground on armature 69 and bar v 68, because relay 94 is locked to the winding of relay 552.- The wipers on shaft 66'will then advance in accordancewith the rate of speed of groundinterrupter device 16, the circuit being traceable through keysprings 104 and 105, armature 106 to bar 103. In any event, it will now require alonger time thaninitially for the wipers-on shaft 66 to advance over the space defined by bars68 and 103, which latter two bars'b'ccu'p'y' like circumferential space, and thus provides for a longer connection holding time, assuming for the present that the same rate of travel of the wipers on shaft 66 ov'e'rthe space controlled by ground interrupter 15 will defined by the bar ensue; This arrangement thus provides for along'er holding time for successive periods than' for' the initial period beentailed "in successive periods. The lowered cause the-manual effort and loss of equipment time'in firstestablishing the connection isnot cost to the operating concern for'successive periods is thus reflected in ,the longeritime the subscriber may hold the connection for a vi -period about to terminate always the same;

change affects the duration in proportion to the time occupied under the different rates because the'change in accordance with the time of day simply varies to advance the wiper from the angular position of bank contact 81 to the normal positionsh'own in the drawing, driven unv der the control of ground interrupter 78 will always be the sameso that thesubscribers will definite advance notice, regardless of the length of the period all- In'casethe-rate change.withicorrespon dence ,to the time of day occurs-during the progress of a connection the lowed forthe unit Of'charge- However,v as;

adverted to before, the speed of the interrupter 78 may be varied in accordance with the time of day, as are interrupters 13 to 16, and

. under certain traflic conditions this may be desirable. Zone keg s for variously altering duration for I specific charge.

With respect to the feature of the present invention which provides for the operator variably setting the zone keys for the different zones, the keys for this purpose operated by plungers 110 and 112 in r 1g. 3 are shown normal for the 'exampled call to a subscribers line (jack 4-9) within the same ofiice district. Were the call to someother district or zone,

one of the key plungers 110 or 112 would be depressed to correspond to the zone or rate applying. This latter substitutes ground interrupters 13 and 14 for interrupters 15 and 16, respectively, or interrupters 17 and 18 for interrupter sl5 and 16, respectively, depending upon which key plunger 110 01 112 is depressed. At the time completing plug 48 is withdrawn in takingdown the connection-and so-called shift-plate action. wherein depressing any one key thereby unlocks any other,

operated key by a movement of the shift-plate 118 while the last depressed plunger is locked down by the shift-plate. The shift-plate is also operated to unlock any depressed key through the agency of armature 119 of the trip-magnet 115, so that the plungers 110 and 112 will be in the up position normally; that is, when the plug 18 is not in a jack. Whilebut two zone-key plungers 110 and 112- are shown, it will be understood there may be any greater or less number of them, together with specific ground interrupters generally like intcrrupters 13 to 18, but having time of day variable speeds with correspondence to the zones represented by the added zone keys.

Number of periods meter.

A meter wheel 120 is operated by the magnet of relay 95 and the dog 121 is. disengaged by the operationof the shift-plate 110 under the influence of thetrip-magnet 115 or a key plunger as 110 or 112, so. that while the wheel 120 is stepped forward at each operation of relay 95, signifying a successive charge period for the particular time of day has expired, it will be restored to normal by its return-spring 122 when the operator with- .draws the plug 48. The operator thus has a meter does not operate for the initial charge.

While the meter-wheel may not be necessary for ordinary calls wherein pie-payment is made, or registration of the call 1s made on a subscribers call meter, it becomes useful in saving clerical work for the operator on calls to suburban and other distant points, for ex ample, where prepayment or registration on a subscribers meter is not made.

Absolute timing of calls.

In this connection, while the different ground interrupter devices 13 to 16 have been said to have variable rates of speed depending upon thetime of, day, it is preferred in the exampled instance, to have the lnterrupter devices 17 and 18 operate at definite, constant rate of speed and be used for suburban or long distance calls, and moreover, that in place of ground being always normally applied to bar'681 from armature 69 it will be thus applied from spring 113 only when key plunger 112 is at normal, and bar 103 connected to ground interrupter 18 when key plunger 112 1s operated, so that the sec- -ond duration period (with zone key plunger 112 depressed) will be the same as the first;

that is, the first period will not be shortened 'terrupter actoncaused by ground from armature 69. This preferred modification is shown in Fig. 4.

Under the last said modification (key 112 depressed) the time of successive cycles of the wipers of the switch B is constant and has a definite time significance corresponding to the speed of the ground interrupter 18. This may be five minutes, for example. So the operator upon observing the meter wheel 120 before taking down the connectionobtains a" record of the number of five-minute periods. However, she has no record of any-fractional period following the last registrationof the meter-wheel 120. The record of the fractional period she may obtain by manipulat ng the key 125 to apply the'voltmeter 126,which is .common to all thecord-pairs of the operators position, to the wiper 126, the voltmeter needle indicating the relative position of wiper 126 and consequently the duration with respect to a full period. Of course, the voltmeter may-be graduated in minutes or other convenient units. The resistor 130 is tapped at uniform points to consecutive bank contacts cooperative with the wiper 126; the said resistor being common to all switches similar to B for the operators position by reason of the individual corresponding bank contacts of the switches cooperative with the wiperscorresponding to 126' being in multiple relation. The drawings do not show the of the periods transpiring.

i "shown connected) 1 has It will be noted,

" depressed the said bank contacts of the other switches as B ofthe operators switchboard '(other switches not being shown). 'to avoid involving the drawingsQ fllie'operator would not operate morethan'one key as 125 at a time. ,The auxiliary 'contactson the right operated by plunger 112 in Fig. 4 (in lieu of key 96 provided for this purpose otherwise) is used to open the lockingjcircuit'for relay- 95 to extinguish the time lamp'l 00 on such calls as last referred to wherein the switch B serves as'an agency to enablev the operator 'to 'de-' termine elapsed time, independent of the time of day variations, assu'mingthe ground interrupters 17 18 and 7 8 are operating at- ,such rates of speeds that the timetaken for the wipers on shaft 66 to'move, from be drawn positions off the right-hand set of bank contacts has a known time interval; five minutes,';for instance, one-fourthminute beingbetween the last two bank contacts.

by reference to Fig. 4, that the conductor leadim through key 96 is loopedthrough a set of normally closed au'xiliary contacts operated by plunger 112' -so that the time lamp 100 (or lamp 145 will flash with'Fig, 6 introduced, as will appear presently) willnot permanently glow, since relay 95 will then not lock, the parties to .the call talkingfwithout interruption from the operator; though rec eiving the periodic tones from sources T and T to keep 'themfadvised In this connection, it will-be understood that the tone suppliedto the bank contacts 81 and 101 of switch B'from'so'urces '1 and T may optionallyhavenormally closed key contacts opened 1 when operating plunger 112, so

the condition of plunger 112 being tone sources T and vT will be disconnected from the bank contacts 81 to 101 that under of switch as B corresponding to the specific depressed. This Will be key plunger as 112 the arrangement atcertam operators switchboards in an ei'zchange where toll connections to long distance hnesare made.

Varidb le speed of ground 'Znterrupters. With reference 'to 5 this shows-a motor C having a speed control apparatus operated by a clock driven'revolving contact-arm 127"Wherein through the agency of resistors v embodiment therefore contemplates three 128, 129 and 130 the speed of the motor may be varied. It will be noted that the contactarm 127 has twenty-four cooperating con tact segments; one for each hour of the day. Each said contact segment (only five being" a conductor leading therefrom to a subordinate switch-arlmnexvcepting for.3 and): oclock, which hours have. the same rate andare common to switch-arm 12 m; 1 2 and 3 oclock p. m. lead to switch I arms 12,- 1, 2' and 3. respectively. The lat- 123.1, '2' and-'3' I interrupter ,16, there will be a similar nio- The contact segments-corresponding to and 3 for. each ground interrupter 13 to 16.

to the resistors 128, 129 and130, so that the latter said switch-arms maybe set at'will to cause the motor C'to have. a pr'e det'ermined speed variable atwill for every hour ofthe day, it being borne in mind that each of the twenty-four segments cooperative with contact-"arm 127 lea'ds to a switcl1 -arm as those shown ,(excepting segments for and 4 ocloek as shown, as wellas others notshown) and that they alsohave common access to the resistors 128, 129 and, 1 30. The motor G drives on its shaft 131a ground interrupter such as 16, for example, so that the frequency of ground interruptions will vary in accordance with the position of the contact-arm 127 corresponding to the concerned time of day.

. It willbe clear that diiferent days of the week, as well as different legaland other holidays mayeach have a specific rate schedule,'-variable from i I accordance with a prearranged rate schedule authorized and published for the information of subscribers. Theexchange attendants will see that the switch-arms 12 and 3 (and switch-arms, for other hours of p the day, not; shown) 4 are properly set by handles 135, 136, 137 and 138,1"espectively, in advance of the hourthey become "effective.

, In this connection, lt will be understood ,thatwhile a single nlotorc and itsspecilio contact-arm, 12T ,,an"d: Switch-arms such as refer to a s ngle ground torandspeed control arrangement, perhaps having a different inherent speed, for each of the ground interrupters 13, 1 1, *and 16, theshaft l iO carrying thecontactmrm 127 being preferably commonto other conagency of the magnet hour to hour at willor 1n 149 will serve to change a all the; interrupter speeds simultaneously, an d therefore becomes ,a convenience and safe- "tact-arms like 127," bi1t the arms as 127 "being "specific-to each of sai-d ground i-nterrupters.

guard against overlooking any interrupter.

, The exampled embodiment contemplates three speeds'of the motor C, controlled by the resistors 128, 129 and 130- Obviously", more) rates of'speeds by the use o f corresponding additional resistors may be employed.v The difierent'charge rates, any one of which may a 1", 2' and 3".corresponding to theconcerncd hour "or hours; The exampledembodiment shows the hours 3 and 4; that is from after 2 oclockpi m. to 4 'oclockp. m. involving-the same speed for interrupter 16;

There a set of Witch-armSli-kc 12', li :2

Of course, if-it is known thatv certain hours of the dayor night dependin g will always havethe same .arn 127 for the saidhours may be tied together in multiple and a single switch-arm will then suffice for the said hours;

lVhile the foreging descriptions have referred to changing by hourly degrees, it is manifest that the stages may .be shorter or longer than an hour; fifteen minutes, or three hours, for example. Under these conditions the segments will span a corresponding angular space, having in mind that for some parts of the day the changes may refer to fractional hours and for other parts of the day the changes may referto a plurality of hours. Moreover, a segment may span the angular space of fractional and even hours, as from 1:30 p. in. to 4:45 p. m. The magnet 149, in stepping the contact-arm 127 will step from intermediate of one segment to intern'iediate of a successive segment, having in mind that where a long segment, perhaps spanning several hours is used, several steps will be required to pass over it. Theangular' space constituting a step will conform to the shortest segment. The latter.- may lie fifteen minutes (the segment subtending 3.75 angular degrees), or it may be four hours (the 5;- ment subtending 15 angular degrees), for example. Under this arrangement the steps will be at 15-minute intervals of 3.75 angular degrees each, the four-hour segment requiring sixteen steps of the contact-arm 127 in pass.- ing over it since it involves; a total of 60 angular degrees.'

It will be understood'that any well known means for varying the speed of rotation of the ground interrupters 13 to 16 may be employed, the variation of the resistance in the shunt winding of the motor C being shown merely by way of example.

With further reference to Fig. 5A and also to Fig. 5B'which show a plan view and an edge view of the circumferential edge ofthe twocontact segments corresponding to 11 and 12 oclock pm. together with the cooperating contact arm 127. The said segments are slightly beveled in thickness upward in the direction of travel of the slightly flexible contact-arm 127 and the long edge of the segments over-hang slightly to insure that when ithe contact-arm 127 clears a segment it will snap into place on the successive segment,

clear of the antecedent segment.

Flashing cord supervisory lamp.

' With reference to Fig. 6 which shows a preferred modification affecting the cord-pair supervisory relay 141, wherein the contact "will be locked attracted so that the battery applied through the added interrupter 144, armature 143, make contact 142, armature of relay 141, will cause the supervisory lamp 145' of the answering cord to flash rapidly to attract the operators attention that the period has terminated so that a new toll may be charged the subscriber. The time lamp 100 will not be required under this condition, though it may be employed. It will be noted that if the operator fails'to respond to the flashing of lamp 145 (or time lamp 100) promptly and the calling party terminates the service before being informed by the operator that the period has expired the operator may by operating key 125 note by the pointer on the voltmeter 126 how far the'time has exceeded into the next period notyet collected or charged for at the time the operator makes the latter observation. Of course, observing the position of wiper 126 will give this, particularly if a scale is provided," but the switch 2 B will not ordinarily be located in view of the operator. g

Timing stopped when calling subscriber kangsup. Fig. 7 shows a preferred modification wherein, the conductor leading to wiper 72 in Fig. 2 is looped through ,a set of normally opemcontacts 47 on supervisory relay 141.

This is so that if the calling subscriber hangs up to terminate the service it will cause the switch B to stop stepping. Then when the operatordepresses the key 125 at .a later .time the time only until the calling subscriber replaced his receiver is recorded against him as indicated by the voltmeter 126. When the operator withdraws plug 48 from ajack and thus permits relay 61 tounlock, ground on its armature- 151 will be applied to restoring b'ar 152,'so if wiper 153 and its shaft 66 is not in its normal position as drawn it will cause the motor mag'net 65 to operate from its interrupter armature 64 to restore'the shaft 66 to its normal position.

Modifications incorporated in preferred 'dmbodzment.

)Vhile the preferred embodiment disclosed herein only as an exemplary one will incorporate the modifications shown in Figs. 4, 6

and 7 it will be understood that said modifications may beomitted without departing from the contemplated invention or use thereof, because conditions of service W111 time oneach of said contacts.

77) to another '(as-1 50). Also, the switchB' nected (in common with othercorresponding l nite lnterval of time remains before the'terinterrupter (not shown) like 78.

period is appliedthe conversation before 'the wiper the said preferred embodiment, but also by amplifying and further modifying it. For example, the, bankfcon tacts 77' and 150 are shown commonly connected to thev ground interrupter 7 8, andilnder, this condition the wiper 72-will rest, for the same length 'of "It'is preferred to have the bankcontact 150jindividually concontactson other switches) to a faster grourn The said faster interrupter willbe timed with respect to interrupter 78 so thatwhen the wiper '72 moves off bank contact 150 itwill remain on say half aslong as'on bank contact- 77.

bank contact 150 for That is, after thetone for the termination of the subscribers will have a short time, lessthan the time advance tone and thefinal tone,to close the y 77 steps to the normal position and off to the first ofinormalv os'ition. That is, therewill be a brief time left after the final toneibelonging to the period paid for or included in the period transpiring 1 Also, it is noted that the momentary ground impulse to the motor magnet is all that is required to step it from one bank contact (as r 18 bank positions. Obviously, this may be made more or less as well as varied as to operative contacts in'the "b ank, bank contacts being possibly introorder to extend duced intermediate of'bank positions shown in the period between operations. Also, in place of the spring 99 being applied to direct ground, it may be connecte 'tothe sleeve of the plug '12'so'ground will be derived through the winding of relay as 8 so that relay 95 will be unlocked by withdrawing plug 12 when taking down the connection. i

Having described the exemplary embodiment in its general operations and structure, and having indicated the preferred ment incorporating illustrated as well as simply described modifications thereof, what 1. In a telephone system, a calling line, a called line, means for connecting the calling line to the called line, a timing device for indicating the length of service between said lines, means for causing said timing device to indicate by signal when a predetermined pe riod of service has elapsed, means for maintaining said signal operated regardless of subscriber control on the calling line in terminating the service, I tomatic means differently operative depending upon-during service durates for altering the length of said predetermined period.

77 onto bank contact between the embodiand clock-controlled auwhat period of the day the accordance withth'e time of day forapplying a signal audible on saidconnectionto apprise the auditor thereof that a substantially defiduration of the connection elapsingregarda less of said specific condition. a

4. In a telephone system, calling and calledlines, a link for connecting said lines for service, means for timing the duration of said connection under control over one of the said lines, a signal device, means for operating said signal' device responsive to apredetermined duration ofthe connection elaps'ing, time controlled automatic means for varying call connection,

j automatic means operated msaid predetermined duration in accordancewith the time of day, and means for maintaining the signal-operated regardlessof control over either of the lines. a

5. In a telephone system, a timing device for measuring variable periods of service tlme occupied by parties of a call connection,

1 time controlled automatic means for varying the length of said periods, and time controlled automatic means for applying a signalaudible on said connection to apprise theaudi tor thereof that a substantially definite. intervalof time remains before the termination of the ensuing period regardless of thelength of the ensuing period.

6. In a telephone system, device, means for starting said device from rest to indicatewhen a substantially predetermined clasped period terminates following said starting, automatic means for varying the speed of said device to in turn vary. thelength of the said period inaccordance with the time ofday, and means for at the same time varying the speed of said device by manual setting at will in accordance with which one of a plurality of keys isoperated,

7. In a telephone system, lines, an operators cord-pair for connecting said lines, a timing device specific to said cord-pair, a normal speed of operation of said device for measuring elapsed time cord-pair, setting keys for varying said normal speed, and automatic means for restoring a toll assessing of connection by said the setting for operating at the'said normal speed responsive to disconnecting the cordfor varying the speed of sending said impulses by said contact so as to vary the elapsed time requiredto operate said signal device responsive to said predetermined plurality of impulses whereby the elapsed time occupied from-the time of applying said control over the called line to the time of operat-v ing the signal devicewill the time of, day the connection durates through. i V

9. 'In a telephone system, a calling line, a called line, a connecting link for joining said lines, a progressively movable switch, a plurality of tone sources, means for starting the movement of said switch responsive to control over the connection, automatic means for applying a first one of said tone sources audi-,

ble on the calling line responsive to a prede termined time elapsingafter said starting- Wherein said predetermined timewill vary dependent upon the time of day, and automatic means for thereafter applying the second of saidvtone sources audible on the call-- mg line responsive to a specific time .elapsing after the application of said first tone source regardless of the time of day. n

10.- In a telephone system, a calling line, a

. called line,-a connecting link for joining said lines, a progressively movable switch having a wiper, automatic means for successively drivlng said wiper a predetermined distance from normal 'startlng position lndlcative of a correspondlng speclfic toll charge foreach said progression, automatic means'forsta'rting the movement of the said Wiper from normal starting position responsive to control over the called line, and automatic means for varying the extent of said wiper movement for a Specific time duration depending upon if the wiper progressed from normal starting position and returned thereto since the'said control over the called line occurred;

11. In a telephone system, a'calling line, a called'line,

time, means'controlled over 'the called line for starting the operation of said timing device, a supervisory signal device, means operatedover the "called linefor successively be determined by a connecting link for joining said lines, a tlmlng device for measuring elapsedv operatingsaid signal device as a supervisory indicator to indicate the responded or nonresponded condition of the called line, and

means governed by the timing device for sucstarting the operation of said timing device,.a

supervisory signal device individual to said link, means operated over the called line for successively operating said signal device as a supervisory indicator. to indicate the responded or non-responded condition of the called line, and means governed by the timing device for successively'operating said signal device after a predetermined lapse of time after said control is effected to signal that the said pre- I determined lapse of time has terminated;

13. In a telephone system, a calling line, a called line, a'connecting link for joining said lines, a timing device, said timing device operating in successive cycles responslve to con- *al over. the called l1ne by the act of response on the called line to initiate it's said cyclic means responsiveoperation, a signal device, to the completion ofthe first said cycle. for

operating said signal device to indicate the termination of the cycle,

means for causing the signal to continue to display regardless .of the fact the timing device is then operating in the nextsuccessive cycle, means for then eftacing the operated state of the signal device, and means 'for again operating the signal device respons ve to the completion of the next-following cycle regardless of the fact that the signalmay have been etfaced intermediate of last said cycle.

14. In a telephone system, a calling line, :1 called line, a connecting link for joining said lines, a timing device, said timing device operating insuccessive cycles responsive to control over the called line by the act ofresponse on the called line to initiate its said cyclic operation, a signal device, means re sponsive to the completion of the first said cycle for operating said signal device to indicate the termination of the-cycle, means for causing the signal to continue to display regardless'of the fact the timing device is then operating in the next successive cycle,-means for then efi'acing the operated state of the signal device, means for again operating the signal device responsive to the completion of the next following cycle re ardless of the fact that the signal may have been efiaced intermediate of last said cycle, and indicating means for disclosing'the number of whole cycles and the extent of excess thereover that the responded condition of the called line was maintained through regardless of the time called line, a

link, means operated v I starting the operation of said switch, means a. is aaaea Cantatas was eta-finned with respect to the time the said disclosure is observed. ';i

' :15. In a telephone system, a' calling line, a link for temporarily connecting said lines, a timing switch individual to the over the 'ealledl'ine for for continuing the operation of said switch in cycles from normal starting position and back to, normal starting position, and means for predetermining theltime consumed for each cycle wherein the tlmeof day i a factor.

I 16. In a telephone system, a calling line, a called line, a'link for temporarily connecting said lines, a timing switch, means operate over the called. line for Starting the operation of said switch, means for continuing theoperation of said switch in cycles from normal starting position and back to normal starting position, means for predetermining the time I consumed for each cycle wherein the time of day is a factor, and means also controlled by the number of cycles which have transpired since said initiation for determining the time p consumed for cycles following.

17 In a telephone system, a calling line, a called line, a link for temporarily connecting said lines, a timing switch, means operated over the called line for vstarting'the opera- .tion of said switch, means for continuing the operation of said switch in 'cyclcs from normal starting posit on back to normal startmg pos tion, an impulse-sender for operating the switch at predetermined speed' by impul ses from said sender to. progress the switch in eflecting saidgcycle's of operation,

- and means exclusive of the impulse sender and depending upon the cycle being the .first cycle of operation after said initiation for causing the switch to operate through a part of said first cycle irrespective of impulses ap- I plied.

18, In a telephone system, a calling line, a called line, a link for temporarily connecting said lines, a timing switch, means operated over the called line for starting the operation v the respective cycles,

starting position, pre-setting means operated for continuing the oper- 1n cycles from normal of said switch, means ation of said switch starting position back to normal starting before said starting for varying the time for position, and manually 0 means for varying v I each respective cycle of a plurality of-sucd started.v

. establishing connection completing the respective cycles, and meansresponsive to completing each said cycle for assessing atoll charge for the connection. 1

called line, a link for temporarily connecting said lines, a timingswitc'h, means operated over the'ealled line 'for 'sta rtlng the opera- "tion of said switch, means for cont-inning the operation of said switch in "cycles from norback to normal starting perated pre-setting the time for completing mal starting position cessive cycles by. a setting operation" performed before the first ofsaid cycles has 21. In a telephone system, a calling line, a called line, a link fortemporarily connecting said lines, over the connection for starting the operation of said switch, means for continuing the operation of said switch in cycles lfrom normal starting position back to normal starting position, pie-setting means operated before said starting for varying the time'for completing the respective cycles, and means responsive to completing each said cycle for assessing a toll charge for the connection.

22; In a toll telephonesystem', means for establishing 7 connection betweenc'a calling line-and a desired called line, means forau'to-. matieally assessing a specific unit toll for a substantially predetermined timeof: service from a random starting point, and time con- *for automatically varying the length of said period in-accordance with the time of day the service is ren-' trolled "automatic means dered.

a timing switch, means operated v 23. In atoll telephone system, nieans for establishing conneetion'between a callingline and a desired called line, means for automatically assessing a specific unit 'toll for a substantially predetermined time of service from a random starting point, the startingpoint being coincident with the response on the called line automatically, and time controlled automatic means for. automatically varying,

the length of said period in accordance with thetime of day theservice is rendered.

24. In a toll telephonesystcm, means for establishingconnection between a calling line and a desired called-line, a' timing mechanism, means'foroperating the timing mechanism from normal home position to home 0- sition in successive cycles, means control ed over the called line for initiating the operation of the timing mechanism 'from the home position,

and means depending'upon whether the cycle is the first or a successive cycle for determining the, length of timefor effecting the cycle. I

'25. Ina toll telephone system, means for between a calling line anda desired called line, a timing mechatermining the length of time for effecting the' cycle, and means for recording a specific charge for each cycle'regardless of the time occupied therein.

26. Ina toll telephone system, means for establishing connection between a calling line and a desired'called line, a timing mechanism, means for operating the timing mechanism'from normal home position to home position in successive cycles, means controlled over the called line for initiating the opera- -tion of the timing mechanism fromhome posit-ion, means depending upon whether the cycle is the first or a successive cycle for determining the length of time for effecting the cycle, .andmeans for displaying an indication of a specific charge for each cycle and fraction thereof regardless of the time occupied therein.

27. In a toll telephone system, means for establishing connection between a calling line and a desired called l1ne, a timing mechanism individual to theconnectiommeans for' operating the timing mechanism from normal home positlon to home posltion 1n successive cycles, means controlled. over the called'line for initiating the operation of the,

timing mechanism from the home position,

and means exclusive ofthe calling line for 1 timing mechanism from home position, and,

variably pre-setting the timing mechanism for pre-determining the length of time of a said cycle.

28. In a toll telephone system, means. for establishing connection between a calling line and a desired called line, a timing mechanism individual to the connection, means for operatmg the tlming mechanlsm from normal home position tothe home position in successive cycles, means controlled over the called line for initiating the operation of the means exclusive of the calling line for presett-ing the timing mechanismfor pre-determining the length of time of successive said cycles, the cycles having different length.

. 29. In a toll telephone system, means'for establishing connection between a calling line and a desired called line, a timing mechanism individual to the connection, means for operating the timing, mechanism from normal home position to the home position 1n successiver cycles, means controlled over ,the

called line for initiating the operation of the timing mechanism from home position, means exclusive of the calling line for changing the settingof the timing mechanism-for predetermining the length of time-of successive said cycles, and means operated autocluding a link circuit for establishing connection between a calling line and a desired called line, a cyclically operating timing mechanism of the link circuit having a home position, an impulse, sending device, the timing mechanism operated through a definite distance from the home position to indicate a predetermined toll charge, means for drivingthe timing mechanism at a predetermined r'ate responsive to the mpulse sending'device to measure the time of a conversation charge period, and automatic means independent of said impulse sen-ding device for advancing the timing mechanism over a portion of said distance, the operation of; last said means depending upon if the movement of the timing mechanism from home position is the first one of the particular call or is a succeeding one, in order that a longer time will be allowed for a. specific toll charge after the time allowed for the-first toll charge has elapsed than was allowed for the first toll charge. 7

31. In a toll telephone system, means including av link circuit for establishing con nection between a calling line and a desired called line, a cyclically operating timing mechanism of the link circuit having a home position, an impulse sending device, the tim ing mechanism operated through a definite distance from the home position'to indicate a'predetermined toll charge, means fordriving the timing mechanism at a predetermined rate responsive to the impulse sending device to measure the time of a conversation charge lastsaid, means depending upon if the movement of the timing'mechanism from home position is the first one of the particular call or is a'succeeding one, in order that a longer time will be allowed for a specific toll charge after the time allowed for the first toll charge has elapsed than was allowed for the first toll charge.

32. In a toll telephone system, a plurality of link circuits, means including a random said link circuit for establishing a connection between a calling line am a desired called line, a timing mechanism for the link circuit, common time controlled means for successively operating the timing device through a predetermined range of movement from a starting point to indicate corresponding'successive unittoll charges, means irrespective of the time controlled means for 0pmeans erating the timing mec anism. over a portion of its range in order to shorten the time occu pied in operating through said range, an

for disabling last said means dependent upon how manytimes said last said means has operated.

33. In a toll telephone system, a plurality of link circuits,-means including a random said link circuit for establishing a connection between a calling line and a desired called line, a timing mechanism for the link circuit,

time controlledmeans for successively oper ating the timing device through a predetermined range of movement from a starting int to indicate corresponding successive unit toll charges, a meter of the link circuit for recording the number of said charges operated responsive to the completion of each operation of the timing device through said range, an adjustable resistor of the timing mechanism, means for varying the resistance included by the resistor in accordance with the position of. he timing device with respect to t e starting point, a source of current, a calibrated current indicator common to said links, means whereby the number of integral units will be indicated by the meter, and

means whereby the relative value of any fractional unitmay be determined by the indicator.

34. In a toll telephone system, means including a link circuit for establishing connection between a calling line and a desired called line, a step-by-step advancing timing switch individual to the link circuit, a plurality of impulse sending devices for operating the timjing switch, a plurality of manually operated set-keys, automatic means 'for causing the timing switch ,to come under the control of one of said impulse sending devices, andmeans res onsive to the operation of a random said set ev for determining which corresponding one 0 said impulse sending devices will control said switch, subject to said automatic means.

35. In a toll telephone system, means for establishing connection between a calling and a called line, a step-by-step advancing timing switch for the connection, means for indicating a unit toll charge for a predetermined range of movement of the switch, automatic means controlled over the connection for causing the timing switch to initiate its operation, means for causing the switch to vary its rate of. movement over certain predetermined portions of its range of movement depending upon an operation effected prior to the movement of the switch, and means whereby each said portion represents a charge element of the total charge represented by said range of movement.

36. In a telephone system, means for establishing a connection from a calling line to a called line, a timing switch, means for automatically starting the timing switch, means for assessing'a toll charge for a predetermined extent of movement of the timing switch,

d means for varying the speed rateof said movement, and means for applying a signal to the connection at a substantially predetermined fixed time before the termination of said extent of movement regardless of said rate of the speed rate of said movement.

37. In a toll telephone system, means for vestablishing connection between a calling line and a desired called line, a call toll register, a cyclically operative timing mechanism for the connection, means controlled over the called line for initiating the operation of the timing mechanism from idle resting position, means for registering a unit tol charge on the call register for the connection responsive to a predetermined portion of the cyclic movement of the timing mechanism, and automaticmeans for causing the timing mechanism to move over said predetermined portion in varied time duration, depending upon it the timing mechanism is operating in its first cycle after the initiation or its operation or is operating in a subsequent cycle.

38. In a toll telephone system, establishing connection between a' calling line and a desired called line, a call toll register, a cyclically operative timing mechanism for the connection, means controlled over the called line for initiating the operation of the timing mechanism from idle resting position, means for registering a unit toll charge on the call register for the connection responsive to a predetermined portion of the cyclic movement of the timing mechanism, and automatic means for causing the timing mechanism to move over said predetermined portion in varied time duration, depending upon the time of day' the connection endures through.

39. In atoll telephone system, means for establishing connection between a calling line and a desired called line, a call toll register, a cyclically operative timing mechanism for the connection, means controlled over the called line for initiating the operation of the timing mechanism from idle resting position, means for registering a unit toll charge on the call register for the connection responsive to a predetermined portion of the cyclic movement of the timing mechanism, automatic means for causing the timing mechanism to move over said predeter- -mined portion in varied time duration, and

automatic means governed by said timing mechanism for applying two spaced signals wherein a first one of said signals indicates a substantially predetermined amount of .said predetermined time duration remains and the second one of said signals indicates that this latter time duration has substantially elapsed, the latter said time between signals being spaced substantially constant means for with respect to each other and also counting back from the termination of said predeterestablishing connection between a calling line and a desired called line, a call toll register, a cyclically operative'timing mechanism for the connection, means controlled over the called line for initiating the operation of the timing mechanism from idle resting position, means for registering a unit toll charge on the call register for the connection responsive to a predetermined portion of the cyclic movement of the timing mechanism, automatic means for causing the timin mechanism to move over said predetermine portion in varied time duration, and automatic means governed by said timing mechanism for applying a signal to indicate that a substantially predetermined amount of said predetermined duration'period re-.

mains, regardless of the length of the predetermined duration period.

In witness whereof, I hereunto subscribe a my name'this twelfth day of May, 1927.

HERBERT M. F RIENDLY 

